1. In your app list , select " settings ".
In your android device , there you may found different applications : system and user. From your app list , select settings. In order to install application(s) , you must have to manage some of your android's settings / functions which you can easily found in setting app.
2. After selecting settings , choose " Security " Under Personal Settings.
After you enter in settings , you will found different settings like Wireless & Network , Device , Personal , Accounts And other also. From these topics , under Personal , Security option is given. You have to select that personal option which is under Personal.
3. Then mark unknown sources.
Inside the Security option , you will found many things of security like lock. In that different options , you have to mark/select Unknown Sources option in order to allow installing android apps from any unknown source. After you mark , you have allow to install app by third-party services.
4. Now , A popup warning window appears ( Click On OK )
Now when your select unknown sources , a pop window will appear in front of you and want to notify you. Then you can remove that window by selecting OK button beside cancel button. Remember , you shouldn't select cancel button otherwise you have to choose again three number point ( unknown sources )
5. Select A App ( .apk File )
Now , you have authorised your android system to let install any supported apps from any known/unknown sources where known source is Google Play Store. You can select a app by downloading it from any browser or app or select a app which you have already in your android memory ( internal or external )
6. Click Next/Install Button.
After you select a app / .apk file , if that app have many permission , two clicks are available i.e. Cancel and Next Choose next again and again until install button appears. And if there are only few or no permission , Two clicks , Cancel and Install. You can directly choose install button. Installing process will start. Wait a few seconds/minutes ( Depending on apk size and Your mobile's speed ). After few time , your app can now found on app list. You can quit by clicking on Done option or lunch that app by selecting Open option.
See its video at here:
This is the best and easy way to install app ( application ) into your android phone. Follow these steps and read all steps so that you will nat get any problem while installing a application. If you have still any problem relating to your android installing , you can comment below or want any thongs else , also comment below or if you have Amy problems/suggestions relating to this site ( Not Including This Or Any Of The Posts ) , feel free to contacting me. A contact option is also provided in the footer of this site.